title: Virulence factors of Enterococcus strains isolated from patients with inflammatory bowel disease.
abstract: OBJECTIVE
  To determine the features of Enterococcus that contribute to the development and maintenance of the inflammatory process in patients with inflammatory bowel disease (IBD).
  
  
  METHODS
  Multiplex polymerase chain reaction (PCR) was applied to assess the presence of genes that encode virulence factors [surface aggregating protein (asa1), gelatinase (gelE), cytolysin (cylA), extracellular surface protein (esp) and hyaluronidase (hyl)] in the genomic DNA of 28 strains of Enterococcus isolated from the intestinal tissues of children with IBD (n = 16) and of children without IBD (controls; n = 12). Additionally, strains with confirmed presence of the gelE gene were tested by PCR for the presence of quorum sensing genes (fsrA, fsrB, fsrC) that control the gelatinase production. Gelatinase activity was tested on agar plates containing 1.6% gelatin. We also analysed the ability of Enterococcus strains to release and decompose hydrogen peroxide (using Analytical Merckoquant peroxide test strips) and tested their ability to adhere to Caco-2 human gut epithelium cells and form biofilms in vitro.
  
  
  RESULTS
  A comparison of the genomes of Enterococcus strains isolated from the inflamed mucosa of patients with IBD with those of the control group showed statistically significant differences in the frequency of the asa1 gene and the gelE gene. Furthermore, the cumulative occurrence of different virulence genes in the genome of a single strain of Enterococcus isolated from the IBD patient group is greater than in a strain from the control group, although no significant difference was found. Statistically significant differences in the decomposition of hydrogen peroxide and adherence to the Caco-2 epithelial cell line between the strains from the patient group and control group were demonstrated. The results also showed that profuse biofilm production was more frequent among Enterococcus strains isolated from children with IBD than in control strains.
  
  
  CONCLUSIONS
  Enterococcus strains that adhere strongly to the intestinal epithelium, form biofilms and possess antioxidant defence mechanisms seem to have the greatest influence on the inflammatory process.
authors.affiliation: Department of Microbiology, Jagiellonian University Medical College, 31-121 Cracow, Poland.
authors.forename: Edyta
authors.initials: E
authors.lastname: Golińska
authors.forename: Anna
authors.initials: A
authors.lastname: Tomusiak
authors.forename: Tomasz
authors.initials: T
authors.lastname: Gosiewski
authors.forename: Grażyna
authors.initials: G
authors.lastname: Więcek
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Machul
authors.forename: Diana
authors.initials: D
authors.lastname: Mikołajczyk
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Bulanda
authors.forename: Piotr B
authors.initials: PB
authors.lastname: Heczko
authors.forename: Magdalena
authors.initials: M
authors.lastname: Strus
mesh_terms: D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics; D001430:Bacteriocins / Q000235:genetics; D018441:Biofilms / Q000254:growth & development; D001706:Biopsy; D018938:Caco-2 Cells; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D003106:Colon / Q000382:microbiology*; D016983:Enterococcus / Q000145:classification / Q000235:genetics* / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism / Q000472:pathogenicity*; D018093:Gelatinases / Q000235:genetics; D006801:Humans; D006821:Hyaluronoglucosaminidase / Q000235:genetics; D006861:Hydrogen Peroxide / Q000378:metabolism; D015212:Inflammatory Bowel Diseases / Q000175:diagnosis / Q000382:microbiology*; D008565:Membrane Proteins / Q000235:genetics; D060885:Multiplex Polymerase Chain Reaction; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D001430:Bacteriocins; D008565:Membrane Proteins; D037521:Virulence Factors; C065937:aggregation substance, Enterococcus faecalis; C120351:cytolysin, Enterococcus faecalis; C116707:enterococcal surface protein, esp; D006861:Hydrogen Peroxide; D006821:Hyaluronoglucosaminidase; D018093:Gelatinases
keywords: Biofilm; Enterococcus; Hydrogen peroxide; Inflammatory bowel disease; Virulence factors